74 



before -4 jy. m. in suusliine were invariably somewhat injured, some of 

 the younger limbs dying back and all the leaves usually shedding. 

 The fallen leaves were all replaced by new growth in a few weeks and 

 no permanent injury was done, but the crop upon such trees was notice- 

 ably reduced. The dropping of leaves from a tree in Florida has 

 comparatively little significance, the trees instead of dying, as they 

 sometimes do in California, putting on new foliage and going along as 

 if nothing special had happened. However, the burning of limbs and 

 injury to bloom is another matter, and therefore midday fumigation 

 can hardly be practiced. AVhile some defoliation occurred with trees 

 fumigated at other times than midday, even after night, it was not 

 strikingly noticeable nor was damage to limbs or evop of sufficient 

 amount to be detected after a few months. Some of this work was 

 done as late as February IS, when the blossoms were beginning to open, 

 some of them being well expanded. The bloom seemed unaffected by 

 the treatment unless the work was done with the sun at high meridian. 



The white fly seemed practically exterminated upon the treated 

 trees. In examining hundreds of leaves from dozens of trees about 

 ten days after they were fumigated, and covering thousands of insects, 

 I was able to find but a single living specimen. If a grove was segre- 

 gated from all others,! have no doubt that one fumigation would 

 render it so nearlj^ clean that it would need no additional attention 

 for two or three years. The great hindrance to its becoming a j)rac- 

 ticable remedy is that few groves are so isolated that the fly will not 

 come to them from neighboring groves, and since the insect seeks 

 young and tender growth for egg-laj'ing purposes there is, x)erliaps, 

 some tendency for it to go to trees that have been fumigated and are 

 therefore ptitting out new growth. Under ordinary circumstances 

 the insect is not a great traveler, though winged, and will often take 

 a whole season, extending over three full broods, to spread over a 

 10-acre grove. Its progress will be marked by the trees showing- 

 sooty mold. 



Special observations were made to determine the effect of the gas 

 upon lady bugs. On the afternoon of January 22, 72 ladybugs, almost 

 all Chilocorus bivubierus, which had fallen to the ground under fumi- 

 gation treatment, were placed in a shallow tin box and left until 

 January 23; at 9.80 a. m. of the latter date 70 beetles were in the 

 box, a few of them active; at 4 p. m. 06 remained in the box, about a 

 dozen of them showing signs of activity. At 8.45 a. m. January 24 

 62 ladybugs were in the box, and 60 at 12.40 p. m. The GO never 

 exhibited signs of animation, all being observed to be dead several 

 days afterwards. January 24, by 1 p. m. , another lot of 176 fallen Imgs, 

 nearly all of the same species as before, was collected and kept in the 

 same manner as the first ones. January '26, at 4.30 p. m., 160 of these 

 were dead, 16 out of the lot having recovered. In the first lot 16 per 

 cent of the whole revived; in the second lot about per cent. 



